Semiconductor processing apparatuses commonly use one or more reactants, i.e., precursors, as source chemicals for performing substrate processes, such as, for example, deposition, cleaning, and etching processes. Such semiconductor processing apparatuses frequently comprise a reaction chamber into which the precursors are supplied in order to perform the desired process. The supply of the precursor to the reaction chamber may be performed by a precursor delivery system and such precursor delivery systems may utilize one or more valves to control the flow of precursor to the reaction chamber.
A precursor delivery system may utilize one or more diaphragm valves positioned in a flow path between a source vessel of the precursor and the reaction chamber to enable flow control of the precursor into the reaction chamber. Precursors, such as vapor phase precursors, may be pulsed into a reaction chamber by the opening and closing of an appropriate diaphragm valve in the precursor delivery system. Diaphragm valves may comprise an actuator configured for opening and closing a flexible diaphragm against a valve seat. When the diaphragm valve is in the open position, the precursor is allowed to pass through a valve channel and enter the reaction chamber. When the diaphragm valve is in the closed position, the diaphragm obstructs the valve channel and prevents the precursor from entering the reaction chamber.
An example of a semiconductor processing apparatus that may utilize a precursor delivery system comprising one or more diaphragm valves is an atomic layer deposition (ALD) apparatus. ALD is a method of depositing thin films on a substrate comprising sequential and alternating self-saturating surface reactions wherein one or more vapor phase precursors may be pulsed into the ALD reaction chamber to enable film deposition. ALD processes may require precise temperature control of the precursors, not only in the reaction chamber, but also in the precursor delivery system utilized to provide the precursor to the reaction chamber. In particular precise temperature of the wetted surfaces of the precursor delivery system, i.e., those surfaces in direct contact with the precursor, may be desired for optimal film deposition and apparatus lifetime.
The wetted surfaces making up the precursor delivery system may include the internal wetted surfaces of the diaphragm valve. For example, if the wetted surfaces of the diaphragm valve exceed the operational temperature window for a particular precursor then the precursor may decompose within the diaphragm valve prior to entering the reaction chamber. Conversely, if the wetted surfaces of the diaphragm valve are below the operational temperature window for a particular precursor, then the precursor may condense or even solidify in the valve channel causing the diagram valve to leak or even blocking the valve channel. Accordingly, a diaphragm valve incorporating means for precise temperature control over the internal wetted surfaces of the diaphragm valve is highly desirable.